Everyone I know is pleasantly obsessed with the color of egg yolks. I was myself among them: The deeper the yellow of the yolk, the more delicious the eggs taste and the healthier I felt after eating them. Have we been kidding ourselves?

It’s true that richly colored yolks often (not always, I’ll explain later) come from the eggs of truly free-range, or pastured, hens, who busily hunt and peck their way to a more varied (and more pigmented) diet. The color of a yolk is due specifically to carotenoids, which are natural pigments found in some plants. A wheat-based diet will produce a pale yellow yolk, while a corn- or alfalfa-based diet yields a darker yellow yolk. On a macro level though, it’s important to understand that a yolk may range in color from pale yellow to orange, but a deeper, richer color is not an indicator of nutritional content.

Unfortunately the industrialized food industry has some tricks to produce a rich dark orange yolk color effect. They give their hens feed laced with paprika or marigolds (a technique developed by Frank Perdue and still going strong both here and in Europe). This clouds the ability to consider yolk color to determine egg quality or possibly nutritional value. But something you can count on is that no matter what, the amount of protein and fat content of an egg yolk remain the same: The yolk of one large egg, contains 6.30 grams of protein and five grams fat. What does vary are the amount and types of various nutrients, fat types, and vitamins, contained in eggs based on the conditions the laying hens are raised and what they fed.

So let’s talk about eggs other nutritional value, specifically vitamins. The Weston A. Price Foundation had UBE Laboratories in Fullerton California analyze egg yolks from the supermarket and from pastured hens. They found two times more vitamin A and 8 times more vitamin D in eggs from hens on pasture. This dovetails with a study done in 1929 which found high vitamin D activity in eggs from chickens raised outdoors and NO vitamin D activity in egg yolks from hens raised inside. (Some carotenoids, like beta-carotene, have nutritional value as our bodies convert beta-carotene into vitamin A, for instance. And other carotenoids that might be present “may have an antioxidant function.”). Any number of studies reveal that chickens raised in a wholesome way, with plenty of time outside to roam and forage, lay eggs that are higher in omega-3s, vitamins D and E, and beta-carotene. They are also lower in cholesterol.

Of course, we all presume that chickens raised on pasture are not ingesting pesticides and other chemicals along with essential vitamins, minerals, and trace elements. You presume wrong, research in both the U.S. and the E.U. has shown that free-range chickens have higher levels of PCBs, simply because they get out more and can peck almost anywhere. Any industry polluting the air nearby can be contaminating the yards where these chickens feed. But is the same true of backyard chickens? Well, it depends on the backyard. If you are enjoying eggs from the hens that are foraging right outside the back door, especially if you are feeding those eggs to young children, get the soil tested. In fact, the New York Times reported, elevated lead levels in the eggs of a number of New York City community gardens, which is depressing on several different levels. Consider if your, or your neighbor’s home was built before 1977 (lead in exterior house paint was banned in US Sept. 1977) chances are your yard contains lead from the house having been scraped and painted over the years. Lead particles blown into your yard from your neighbor or dropped from scraping for repainting remains there for life, it cannot be neutralized by any means other than removal. So the underlying consideration here is, if you are buying free-range or backyard eggs, know where and how the laying chickens are being raised.

No matter what kind of eggs you prefer be aware that salmonella can be a problem in them all, even those from organic, and/or pastured or backyard ones. Minimize the risk by proper handling: Store eggs in the refrigerator (I don’t care what they do in Europe), and wash toughly your hands and any utensils that touch them.

The egg section in your grocery store is stocked with many varieties of eggs. Some specialty eggs appear to be healthier than the regular white eggs. But are they really worth the extra money?

EGG PROFILES:

Brown eggs: Eggshell color can vary but it has nothing to do with the quality, flavor, nutritive value*, cooking characteristics or shell thickness of an egg. The eggshell color only depends upon the breed of the hen.

Organic eggs are produced by hens fed certified organic grains without most conventional pesticides and fertilizers. Growth hormones and antibiotics are also prohibited. Organic eggs have the same nutritive value*, fat or cholesterol as regular eggs.

Free-Run or Cage-free eggs are produced by hens that are able to move about the floor of the barn and have access to nesting boxes and perches. The nutritive value* of these eggs is the same as that of regular eggs.

Free-Range eggs are produced in a similar environment as cage-free eggs but hens have access to outdoor runs as well. The nutritive value* of these eggs is the same as that of regular eggs.

Processed eggs such as liquid egg whites or dried egg whites are shell eggs broken by special machines then pasteurized before being further processed and packaged in liquid, frozen or dried form. Process egg products may also contain preservatives and flavor or color additives. Their nutritive content varies by their industrial processing method.

*(The term “nutritive value” as used above here refers only to the eggs “overall” fat and protein being the same for all eggs. Differences in the variety and amounts of: fat type, cholesterol, minerals and vitamins varies with each chicken raising method and feed type).

Are growth hormones and antibiotics used on egg laying hens? While all laying chickens are vaccinated, growth promoters and hormones are not used in egg farming. No pharmaceuticals are given to chickens in healthy flocks. Monitoring of both the flock and eggs ensures that pharmaceuticals are used only when necessary to fight illness in any bird.

Eggs and Cholesterol: How Many Eggs can I eat a week? The average egg has 212mg of cholesterol and some less based on how the hens were raised and the feed they were fed. Since the recommendation for cholesterol consumption is about 300 mg per day, the large amount of cholesterol in eggs may prevent many people from eating them. The cholesterol in eggs really shouldn't scare you away from eggs completely. Most of the cholesterol in your body is made by your liver and the amount of cholesterol in your diet may not have as big an impact on your blood cholesterol or other blood-fats.

Studies have shown that healthy adults can enjoy an egg every day without increasing their risk for heart disease. A study by the Harvard School of Public Health found no significant link between eating eggs and developing heart disease among healthy individuals. However, if you have high cholesterol or known risks for heart diseases, the National Cholesterol Education Program (NCEP) recommends not eating more than 2 egg yolks per week (you can have as many egg whites as you like).

What’s the bottom line? Make no mistake about it, eggs are a wonderful food: An egg is perhaps the simplest shortcut to a quick, inexpensive, nutritious, and delicious meal. Eggs are a nutrition powerhouse, rich in folate, vitamin B12, omega-3 and omega-6 fatty acids. Eggs also provide a good source of lutein, a type of antioxidant. Just choose your best source for the eggs you and your family eat and don’t be afraid to enjoy them.